• Journal of the Korea Society for Simulation
• /
• v.3 no.1
• /
• pp.43-53
• /
• 1994

With remarkable progress of hardware technologies, multiprocessor systems equipped with thousands of processors will be available in near future. In order to increase the performance of these systems, many processor allocation algorithms have been proposed. However, few studies have been conducted in order to compare the performance of these algorithms. In this paper, simulation techniques are used in order to compare the performance of the processor allocation algorithms proved to be useful. These are: an algorithm using equipartion, an algorithm using average parallelism, an algorithm using execution signatures, and an algorithm using the number of tasks in a task precedence graph. Simulation shows that the algorithm using execution signatures performs best while the algorithm using average parallelism performs worst with small allocated processors. Surprisingly, the algorithm using equipartition performs well despite the fact that it has smallest overhead. Overall, it can be recommended that the algorithm using equipartition be used without any execution history and that the algorithm using execution signatures be used with some execution history.

• Journal of the Korea Society for Simulation
• /
• v.3 no.1
• /
• pp.89-98
• /
• 1994

In this paper, a criteria for selecting an appropriate load redistribution algorithm is devised so that a fault-tolerance distributed system can operte at its optimal efficience. To present the guideline for selecting redistributing algorithms, simulation models of fault-tolerant system including redistribution algorithms are developed using SLAM II. The job arrival rate, service rate, failure and repair rate of nodes, and communication delay time due to load migration are used as parameters of simulation. The result of simulation shows that the job arrival rate and the failure rate of nodes are not deciding factors in affecting the relative efficiency of algorithms. Algorithm B shows relatively a consistent performance under various environments, although its performance is between those of other algorithms. If the communication delay time is longer than average job processing time, the performance of algorithm B is better than others. If the repair rate is relatively small or communication delay time is longer than service time, algorithm A leads to good performance. But in opposite environments, algorithm C is superior to other algorithms.

• Journal of the Korean Society for Precision Engineering
• /
• v.32 no.2
• /
• pp.135-140
• /
• 2015

It is an important thing for a designer to simulate and predict the performance of a spindle and a rotary table. In addition to the general performance such as static stiffness, the error motion performance information is beneficial to the designer in many cases. However for an aerostatic bearing the fluid film physical status should be calculated in order to simulate those performances and the calculation time is another obstacle for a simple performance simulation. In this paper the investigation on experiment and simulation is performed in order to find a more effective simulation method for the rotational error motion.

• Journal of the Korea Society for Simulation
• /
• v.8 no.2
• /
• pp.1-11
• /
• 1999

Advanced information communication processing system mainly consists of network access subsystems and a switching system. This paper provides performance analysis of a typical network access subsystem. The network access subsystem is modeled as a queueing network including a server providing polling services. The arrival process of messages to an input buffer is regarded as a Poisson process. Performance measures such as mean input buffer length and mean waiting time of meassages are obtained through simulation, for it is impossible to calculate the performance measures using an analytical method. Hybrid simulation is used to reduce the variance of estimators. The variance reduction effect on the mean waiting time is reported.

• Journal of the Korea Society for Simulation
• /
• v.1 no.1
• /
• pp.87-102
• /
• 1992

This paper presents the development of event-driven system level simulation tool SMPLE(Smpl Extende, an extention fo smpl) and its application to the performance analysis of multiprocessor computer systems. Because of its data structure, it is very difficult to change, expand or add new functions to simulation language smpl implemented by MacDougall. In SMPLE, we change data structure with structure and pointer, add new functions, and enable dynamic memory management. Using new data structure, facilities, and functions added in SMPLE, we simulate job processing of a shared bus multiprocessor system with autonomous hierarchical I/O subsystem. We set system performance contribution of subsystems and units. The impact of disk I/O on system performance is evaluated under vairous conditions of number of processors, processing power, memory access time and disk seek time.

• International Journal of Advanced Culture Technology
• /
• v.9 no.4
• /
• pp.94-101
• /
• 2021

This study is quasi-experimental study of nonequivalent control group pretest-posttest design which applied simulation nursing education programs by standardized patient instructor to look into the effect on the Teaching Effectiveness and Clinical Nursing Performance of nursing students. There was a significant difference between two groups in the Teaching Effectiveness of the nursing students(t= 3.68, p<0.001). There was a no significant difference between two groups in the Clinical Nursing Performance of the nursing students.(t = 1.724, p = 0.089). The simulation nursing education by standardized patient instructor program can help then relieve the Teaching Efficacy of the nursing students. In addition, it is required to develop an appropriate simulation nursing education by standardized patient instructor program considering level and experience of nursing students.

• Korean Journal of Adult Nursing
• /
• v.22 no.4
• /
• pp.375-383
• /
• 2010

Purpose: The purpose of this study was to examine if simulation training affects new graduate critical care nurses' knowledge, self-efficacy, and performance ability in emergency situations. Methods: Forty new graduate critical care nurses were randomly assigned to either an experimental or a control group. The experimental group had didactic with simulation. The control group received only didactic without simulation about emergency situations. The data were collected before and after the training interventions. An independent t-test used for difference among variables. Results: There were no significant demographic differences between the two groups or any differences on data collected knowledge, self-efficacy and performance ability. Following the training, there were significant performance ability scores (p<.001) among the nurses receiving didactic with simulation. There were no significant difference between the two groups relative to knowledge scores (p=.117), or the self-efficacy scores (p=.100). Conclusion: This study showed that simulation training for new graduate critical care nurses is useful to improve performance ability on emergency situations. Hence, providing simulation training to critical care nurses during an orientation period would improve quality of critical care nursing and help the new graduates nurse's adaptation.

• Journal of Advanced Marine Engineering and Technology
• /
• v.25 no.3
• /
• pp.605-616
• /
• 2001

Generally, there are two methods in researching internal combustion engines. One is by experimental research and the other is by computer simulation. The experimental research has many merits that researchers can get data for engine performance, but it has also some demerit of cost and time. If there is an engine simulation code with accuracy for the solution, it is very convenient to predict the performance and optimum design value of the engine. In this study, engine performance simulation program has been improved to predict the transient variation of properties of gas in cylinder, intake and exhaust manifolds, There total program code was developed to calculate the pressure, flame factor and turbulent intensity, As a result of present study, the authors could predicted the in-cylinder pressure, intake manifold pressure and the engine performance in various conditions. The authors also could easily prepare the tool if optimum design of manifold and in-cylinder geometry.

• IE interfaces
• /
• v.9 no.2
• /
• pp.191-202
• /
• 1996

A variety of approaches on performance evaluation modeling have appeared in the technical literature for flexible manufacturing systems(FMS) which can be evaluated only through computer simulation. This study represents a comparative approach for FMS performance evaluation modeling based on reliability, availability and maintainability, and life cycle cost. The methodology proposed in this research includes the following three-step generative approaches. First, a static model to find the initial system configuration is considered under the assumption that the system availability is given as one (failure and maintenance are not considered), and in second step, a stochastic simulation is proposed to serve as a performance evaluation model for FMS with stochastic failure and repair time. In the last step, we developed a simulation modeling using a simulator, FACTOR/AIM to consider a variety of performance factors and dynamic behavior of FMS. Also the applicability and validity of the proposed approaches has been tested and compared through the results of a sample problem using computer programs and procedures developed in each step.

• Journal of the Korea Society for Simulation
• /
• v.4 no.2
• /
• pp.1-16
• /
• 1995

The performance of a computer system depends on the system architecture and workload, and the high performance required in many applications can be achieved by the scalability of the system architecture and workload. This paper presents scalable workload, a performance metric of scalable speedup and hierarchical modeling for the scalable computer system as well as the development of the object-oriented simulator spmplC++ Which is an advanced C++ version of the discrete event-driven simulation environment smplE. In addition, this paper presents two examples of applying scalable speedup, hierarchical modeling and simulator smplC++ to analyze the performance effect of the sclcbility in a multiprocessor system and a network-based client/server system.